Brown (B Locus/Chocolate/Liver)

Quick Summary

The Brown gene dilutes eumelanin (black pigment) to brown but does not affect phaeomelanin (red/yellow pigment).

Black and Chocolate Labrador Retrievers
Black Labrador Retriever (left); Chocolate Labarador Retriever (right) with black pigment diluted to brown

Phenotype: Black pigment (if present) is diluted to brown; red/yellow dogs have brown noses and brown foot pads.

Mode of Inheritance: Autosomal recessive

Alleles: B = Full color, b = Brown

Breeds appropriate for testing: Many breeds

Explanation of Results:

  • Dogs with B/B genotype are expected to express undiluted black pigment. They cannot transmit this brown variant to any of their offspring.
  • Dogs with B/b genotype are expected to express undiluted black pigment and are carriers of brown. They will transmit the brown allele to 50% of their offspring.
  • Dogs with b/b genotype are expected to express diluted black pigment. Black pigment (if present) is diluted to brown; red/yellow dogs have brown noses and foot pads. These dogs will transmit the brown allele to all of their offspring.

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Price

$45 one test per animal
$65 two tests for coat color/fur type/bobtail (same animal) (excludes Cocoa)
$85 three tests for coat color/fur type/bobtail (same animal) (excludes Cocoa)
+ $15 each additional test if ordering more than three coat color/fur type/bobtail tests on the same animal (excludes Cocoa)

Panels Available
Additional Details

English Springer Spaniel
English Springer Spaniel with brown (aka "liver") coat

The Brown gene (TYRP1), also called the B Locus, is responsible for brown versus black coat colors in dogs as well as many other mammals. In dogs, five different variants have been identified that contribute to brown. The VGL tests for the three most common found across breeds and uses the combination of the genotypes at each of these variants to define the alleles present. We report these as the dominant (B) and the recessive brown (b). Two copies of brown (b/b) are needed to change the appearance of eumelanin (black pigment) to brown in both hair follicles and skin. TYRP1 does not affect phaeomelanin (red/yellow pigment).

A dog must be homozygous for brown (b/b) and able to produce eumelanin (at least one copy of the E allele at MC1R) in order to express a liver/brown/chocolate phenotype. Because red or yellow dogs that are e/e at MC1R produce only phaeomelanin in their hair follicles, their coat color is not affected by the brown allele. However, two copies of brown (b/b) will change nose and foot pads from black to brown, even in e/e dogs with red or yellow coats.

Recently a variant in another gene was identified to cause the "non-testable chocolate" in French Bulldogs, known as cocoa.

 

 

Note regarding French Bulldogs: The dark chocolate color of French Bulldogs will not be detected by the brown gene test. For a test to detect the brown color specific to French Bulldogs, see Cocoa.
Turnaround Time
3-6 business days

Species

Dog

Breed

Crossbred Affenpinscher Afghan Hound Africanis Aidi Ainu Dog Airedale Terrier Akbash Dog Akita: American type Akita: Blend, Other Akita: Japanese type Akita: Unregistered Alaskan Husky Alaskan Klee Kai Alaskan Malamute Alaskan Sled Dog Alpine Dachsbracke AMB/AMBOR American Bandogge Mastiff American Blue Gascon Hound American Bulldog American Bully American Eskimo, Miniature American Eskimo, Standard American Eskimo, Toy American Foxhound American Hairless Terrier American Pit Bull Terrier American Staffordshire Terrier American Water Spaniel Anatolian Shepherd Dog Anglo-Francais de Moyen Venerie Anglo-Francais de Petite Venerie Appenzeller Ariegeois Armant Aryan Molossus Aussiedoodle Australian Cattle Dog Australian Cobberdog Australian Domestic Dog Australian Kelpie Australian Labradoodle Australian Shepherd Australian Shepherd, Miniature Australian Terrier Austrian Black & Tan Hound Austrian Pinscher Austrian Shorthaired Pinscher Austrian Smoothhaired Hound Azawakh Bali Street Dog Barbet Basenji Basque Sheepdog Basset Artesian Normand Basset Bleu de Gascogne Basset Fauve de Bretagne Basset Hound Bavarian Mountain Hound Beagle Beagle Harrier Bearded Collie Beauceron Bedlington Terrier Belgian Griffon Belgian Laekenois Belgian Malinois Belgian Mastiff Belgian Sheepdog Belgian Tervuren Bergamasco Berger de Pyrenees, Smooth Muzzled Berger du Languedoc Berger Picard Berner Laufhund Berner Neiderlaufhund Bernese Mountain Dog Bichon Frise Biewer Biewer Terrier Biewer Yorkshire Terrier Biewer, Biro Billy Black & Tan Coonhound Black Forest Hound Black Mouth Cur Black Russian Terrier Bloodhound Blue Lacy Bluetick Coonhound Bolognese Border Collie Border Collie Cross Border Terrier Borzoi Bosnian Roughhaired Hound Boston Terrier Bouvier Des Ardennes Bouvier Des Flandres Boxer Boykin Spaniel Bracco Italiano Braque d'Auvergne Braque de l'Ariège Braque du Bourbonnais Braque Dupuy Braque Francais, de Grande Taille Braque Francais, de Petite Taille Braque Saint-Germain Brazilian Terrier Briard Briquet Griffon Vendeen Brittany Broholmer Bruno Jura Laufhund Brussels Griffon Bull Terrier Bulldog Bullmastiff Ca De Bestier Cairn Terrier Canaan Dog Canadian Cur Canadian Eskimo Dog Cane Corso Canis lupus Cardigan Welsh Corgi Carolina Dog Catahoula Leopard Dog Catalan Sheepdog Caucasian Ovcharka Cavalier King Charles Spaniel CB Romanesc Carpatin Central Asian Shepherd Cesky Fousek Cesky Terrier Chart Polski Chesapeake Bay Retriever Chien d'Artois Chien Francais Blanc et Noir Chien Francais Blanc et Orange Chien Francais Blanc et Tricolore Chihuahua Chinese Crested Chinese Foo Dog Chinook Chortaj Chow Chow Cimarron Uruguayo Cirneco dell'Etna Clumber Spaniel Cockapoo Cocker Spaniel, American Cocker Spaniel, Unknown Variety Collie Cook Island Feral Dog Coton de Tulear Coyote Croatian Sheepdog Curly-Coated Retriever Czech Wolfdog Czechoslovakian Vlcak Dachshund Dalmatian Dandie Dinmont Terrier Danish Broholmer Danish/Swedish Farmdog Denmark Feist Deutsch Kooiker Deutsch-Drahthaar Deutsche Bracke Deutscher Wachtelhund Dingo Doberman Pinscher Dogo Argentino Dogue de Bordeaux Drentse Patrijshond Drever Dunker Dutch Malinois Dutch Shepherd, Longhaired Dutch Shepherd, Roughhaired Dutch Shepherd, Shorthaired Dutch Smoushond East European Shepherd East Siberian Laika English Bulldog English Cocker Spaniel English Coonhound English Foxhound English Mastiff English Setter English Shepherd English Springer Spaniel English Toy Spaniel English Toy Terrier Entlebucher Epagneul Bleu de Picardie Epagneul Breton Epagneul Francais Epagneul Picard Epagneul Pont-Audemer Estonian Hound Estrela Mountain Dog Eurasian Farm Collie Fell Hound Fell Sheepdog Field Spaniel Fila Brasileiro Finnish Hound Finnish Lapphund Finnish Spitz Flat-Coated Retriever Fox Fox Terrier, Smooth Fox Terrier, Wire French Bulldog Galgo Espanol German Drahthaar German Hunt Terrier German Longhaired Pointer German Pinscher German Sheeppoodle German Shepherd German Shorthaired Pointer German Wirehaired Pointer German Wolfspitz Giant German Spitz Giant Schnauzer Glen of Imaal Terrier Golden Retriever Goldendoodle Gordon Setter Gr Ang-Fr Tricolor Hound Gr Ang-Fr W & B Hound Gr Ang-Fr W & O Hound Grand Anglo-Francais Grand Basset Griffon Vendeen Grand Bleu de Gascogne Grand Gascon-Saintongeois Grand Griffon Vendeen Great Dane Great Pyrenees Greater Swiss Mountain Dog Greek Harehound Greek Sheepdog Greenland Dog Greyhound Griffon Bleu De Gascogne Griffon Fauve de Bretagne Griffon Nivernais Haldenstovare Hamiltonstovare Hanoverian Hound Harlequin Pinscher Harrier Havana Silk Havanese Hawaiian Poi Dog Heading Dog Hertha Pointer Hovawart Huntaway Hygenhund Ibizan Hound Iceland Dog Inca Hairless Dog Inuit Sled Dog Inuit Sled Dog Mix Irish Red & White Setter Irish Setter Irish Terrier Irish Water Spaniel Irish Wolfhound Islandsk Farehund Istrian Hound, Smoothhaired Istrian Hound, Wirehaired Italian Greyhound Italian Hound Jack Russell Terrier Japanese Chin Japanese Spitz Japanese Terrier Jindo Dog Jura Neiderlaufhund Kai Dog Kangal Dog Kangaroo Dog Karakachan Karelian Bear Dog Karelo-Finnish Laika Kayo Inu Keeshond Kerry Beagle Kerry Blue Terrier King Shepherd Kintamani Dogs Kishu Komondor Kooikerhondje Koolie Korean German Shepherd Kraski Ovcar Kromfohrlander Kuvasz Kyi Leo Labradoodle Labrador Retriever LabxGolden Laekense Lagotto Romagnolo Lakeland Terrier Lamalese Lancashire Heeler Landseer Lapinporokoira Lapponian Herder Large Munsterlander Large Spanish Hound Latvian Hound Leonberger Leopard Cur Leopard Hound Levesque Lhasa Apso Lithuanian Hound Llewellin Setter Lowchen Lundehund Lurcher Luzerner Laufhund Luzerner Neiderlaufhund Magyar Agar Majestic Tree Hound Maltese Manchester Terrier Manchester Terrier, Toy Maremma Sheepdog Maremma Sheepdog Mastiff Matthes Lion Hound McNab Middle Asian Owtcharka Mi-Ki Miniature American Shepherd Miniature Bull Terrier Miniature Goldendoodle Miniature Pinscher Montenegrin Mountain Hound Moscow Longhaired Toy Terrier Moscow Watchdog Mountain Cur Mudi Mullins Feist Native American Indian Dog Neapolitan Mastiff New Guinea Singing Dog Newfoundland Norfolk Terrier Norrbottenspets North American Shepherd Northeasterly Hauling Laika Norwegian Buhund Norwegian Elkhound Norwegian Elkhound, Black Norwegian Lundehund Norwich Terrier Nova Scotia Duck Tolling Retriever Old Danish Bird Dog Old English Sheepdog Olde English Bulldogge Otterhound Owczarek Podhalanski Papillon Parson Russell Terrier Patterdale Terrier Pekingese Pembroke Welsh Corgi Perdiguero de Burgos Perdiguero Navarro Perdiguero Portugueso Perro de Pastor Mallorquin Perro de Presa Canario Perro de Presa Mallorquin Peruvian Hairless Dog Peruvian Inca Orchid Petit Basset Griffon Vendeen Petit Bleu de Gascogne Petit Brabancon Petit Gascon-Saintongeois Petit Griffon Bleu de Gascogne Phalene Pharaoh Hound Pit Bull Plott Hound Podenco Canario Podengo Portugueso Grande Podengo Portugueso Medio Podengo Portugueso Pequeno, Smooth Podengo Portugueso Pequeno, Wirehaired Pointer Poitevin Polish Hound Polish Lowland Sheepdog Polish Owczarek Podhalanski Polski Owczarek Nizinny Pomeranian Pomsky Poodle, Miniature Poodle, Standard Poodle, Toy Poongsan Dog Porcelaine Portuguese Cattle Dog Portuguese Pointer Portuguese Sheepdog Portuguese Water Dog Posavac Hound Prager Ratter Pudelpointer Pug Puli Pumi Pyrenean Mastiff Pyrenean Shepherd Rafeiro do Alentejo Rat Terrier Red & White Setter Redbone Hound Rhodesian Ridgeback Ridgeback Cross Rottweiler Rumanian Sheepdog Russell Terrier Russian Harlequin Hound Russian Hound Russian Samoyed Laika Russian Spaniel Russkiy Toy Russo-European Laika Saarlooswolfhond Sabuesos Espanol de Monte Sabuesos Espanol Lebrero Saint Bernard Saint Hubert Jura Laufhund Saint Usage Spaniel Saluki Samoyed Sanshu Dog Santal Hound Sapsaree Sarplaninac Schapendoes Schillerstovare Schipperke Schnauzer, Miniature Schnauzer, Standard Schweizer Laufhund Schweizer Neiderlaufhund Scottish Collie Scottish Deerhound Scottish Terrier Sealyham Terrier Segugio Italiano a Pelo Forte Segugio Italiano a Pelo Raso Seppala Siberian Sleddog Serbian Hound Serbian Tricolor Hound Shar Pei Shetland Sheepdog Shiba Inu Shih Tzu Shikoku Shiloh Shepherd Dog Shiloh Shepherd, ISSA Siberian Husky Silken Windhound Silky Terrier Skye Terrier Sloughi Slovak Cuvac Slovakian WH Pointing Dog Smalandsstovare Small German Spitz Small Munsterlander Soft Coated Wheaten Terrier South African Boerboel Mastiff South Russian Ovcharka South Russian Steppe Hound Spanish Alano Spanish Mastiff Spanish Water Dog Spinone Italiano Sporting Lucas Terrier Springer Spaniel Sri Lankan Dog Stabyhoun Staffordshire Bull Terrier Standard German Spitz Stephens Stock Stichelhaar Strellufstover Stumpy-Tail Cattle Dog Styrian Roughhaired Mountain Hound Sudanese Dog Sussex Spaniel Swedish Elkhound Swedish Lapphund Swedish Vallhund Tahltan Bear Dog Taigan Tamaskan Tasy Teddy Roosevelt Terrier Telomian Tengger Dog Tenterfield Terrier Thai Ridgeback Thornburg Feist Tibetan Mastiff Tibetan Spaniel Tibetan Terrier Tosa Inu Tosa Ken Toy Fox Terrier Toy German Spitz Transylvanian Hound, Long Transylvanian Hound, Short Treeing Feist Treeing Tennessee Brindle Treeing Walker Coonhound Turkish Feral Dog Turkish Greyhound Tyrolean Hound Tyroler Bracke Vasgotaspets Vizsla Volpino Italiano Walker Coonhound Weimaraner Welsh Hound Welsh Sheepdog Welsh Springer Spaniel Welsh Terrier West Highland White Terrier West Siberian Laika Westphalian Dachsbracke Wetterhoun Whippet Whippet, Longhaired Whippet, Longhaired Cross White Shepherd Wirehaired Pointing Griffon Wirehaired Vizsla Wolf Wolf Hybrid Working Dog X-Bred Coonhound Xoloitzcuintli Xoloitzcuintli, Toy Yorkshire Terrier Unknown
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Type of Test

Results Reported As
Test Result Brown (Chocolate/Liver)
B/B Does not carry brown. Cannot have brown offspring.
B/b 1 copy of brown present. Carrier.
b/b 2 copies of brown present. Black pigment (if present) is diluted to brown; red/yellow dogs have brown noses and foot pads.
References

Newton, J.M., Wilkie, A.L., He, L., Jordan, S.A., Metallinos, D.L., Holmes, N.G., Jackson, I.J., & Barsh, G.S. (2000). Melanocortin 1 receptor variation in the domestic dog. Mammalian Genome, 11, 24-30. doi: 10.1007/s003350010005

Schmutz, S.M., Berryere, T.G., & Goldfinch, A.D. (2002). TYRP1 and MC1r genotypes and their effects on coat color in dogs. Mammalian Genome, 13, 380-387. doi: 10.1007/s00335-001-2147-2

Schmutz, S.M., Berryere, T.G., Ellinwood, N.M., Kerns, J.A., & Barsh, G.S. (2003). MC1R studies in dogs with melanistic mask or brindle patterns. Journal of Heredity, 94(1), 69-73. doi: 10.1093/jhered/esg014